Radioreceiving system



R. H. MARRIOTT. RADIORECEIVING SYSTEI.

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Patented Mar. 15, 1921"v 3 SHEETS-SHEET 2 RECEIVER R. H. MARRIOTT.

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ROBERT H. MARRIOTT, OF BREMERTON, WASHINGTON.

RADIORECEIVING SYSTEM.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Gontinuation of application Serial No. 138,728, led December 2'6, 1916. This application led Septemv ber 22, 1920. Serial No. 412,089.

(FILED UNDER THE ACT 0F MARCH 3, 1883, 22 STAT. L., 625.)

To all wh-om it may concern Be it known that I, ROBERT H. MARRIOTT, a citizen of the United States of America, and resident of the city of Bremerton, in the county of Kitsap and State of 'Washington, have invented certain new and useful Improvements in Radioreceiving Systems, of which the following is a specification.

This application is made under the act of March 3, 1883, chapter 14:3, (U. S. Statute XXII, page 625,) and the invention herein described and claimed may be used by the Government of the United States, or any of its officers or employees in the prosecution of work for the United States, or by any persons in the United States without the payment of any royalty thereon.

This invention relates to means for treating disturbing electric forces which have a capacity for producing violent, impulse or surge producing effects, sopas to neutralize or cut out such effects before they reach instruments upon which teii' action might be detrimental and -to do this in such a way that other electric currents of a more sustained or periodic character will not be seriously interfered with in their transmission to and action upon the same instruments.

It is the object of this invention to cause the undesirable currents, the effects of which it is desired to dissipate or neutralize, to produce two currents of definite but different periods, then to transform one of these currents into a current of the same period as the other and then, by combining these two currents after they have been made of the same period, cause both to be neutralized, thus radio receiving systems in which my invention has been incorporated, the same representing the arrangements and combinations of parts which are well adapted for illustrating the principles involved in my invention.

Figure 1 represents a form of antenna useful with my invention.

Fig. 2 is a plan view of an antenna.

Fig. 3 represents a system in which two antennae are employed, so connected with other parts that the objectionable effects produced in one circuit are counteracted by the like effects in the other.

Fig. 4 is a double antenna system designed for the neutralization of audio frequency disturbances.

Fig. 5 represents a method of neutralizing audio frequencies due to atmospherics set up in a radio receiver or amplifier.

Fig. 6 is similar to Fig. 5, but illustrating the use of a specific type of rectifier.

Fig. 7 is a diagram indicating the manner of installing my invention for Securing the desired results, irrespective of the question of whether audio frequencies or radio frequencies are employed.

This invention is particularly well adapted for use in radio signaling, to neutralize the disturbing eects produced by electric discharges or pulsations, such for instance as are commonly referred to as static, by interruptions produced in power currents, as by opening and closing switches, and by variations of many kinds, whether produced accidentally or by design, in electric currents which may be capable of producing surges or impulsive action on the receiving circuit; yet it is not limited to this particular field of use but is also applicable to the control of currents of much greater strength and power, irrespective of the use to` which they maybe applied. It may be applied to the control of power transmission lines and their protection against surges set up therein from any cause. I will more particularly describe the application of my invention to radio telegraphy, as that is a field wherein {1;11 is at present more particularly applica- Referring to Fig. 1,'the device represented as a whole by thevcharacter 1, represents an antenna and is of rectangular outline, consisting of an upper section 11, vertical sections 12 and 14, and bottom section 13, the latter being shown as grounded. This also includes one coil 15 of a coupler 15, 1G. through which the impulses are transferred to the receiving or translating mechanisms.

In the associated or receiving circuit 2 which contains the other coil 16 of the coupler, 20 represents a detector, 21 and 22 condensers, and 3, a translating mechanism, here shown as a telephone` Considering Fig. 1, a direct discharge of a disturbing or violently shocking character to the upper arm 11 of the antenna at point X flows in approximately equal quantities in opposite directions producing minimum excitation of the antenna circuit at the period to which the antenna and receiving circuits are adjusted, thereby minimizingthe effect of the direct discharge to the antenna so far as concerns the receiving of radio messages sent on wave lengths corresponding to the period of said circuits.

The top wire 11 of the antenna circuit of Fig. 1 is indicated by the lines 11 in Fig. 2. Electromagnetic waves produced by more or less distant discharges in direction N or S from the antenna of Fig. 2, tend to `produce currents in opposite directions from a through both branches 12 and 14 to earth, thereby minimizing the excitation of the antenna in the period to which it is adjusted for radio messages.

More or less distant discharges occuring in the general direction 1V and E from the antenna 11 tend to produce more or less opposing currents in the antenna to earth but they also excite the antenna radio signal circuit 1, as shown in Fig. 1, producing current of the radio signal frequency to which it is adjusted. Up to this point disturbances from direct discharge, from distant discharges in directionsNandSand a portion of those from direction T andEhave been neutralized, still leaving at times an objectionable remainder in the form of radio frequency alternating current flowing in the antenna circuit at the period to which this circuit is adjusted.

The decrement of this remaining current is dependent on the constants of the antenna radio signal circuit and is therefore more or less similar in radio frequency and decrement to the radio frequency and decrement of the signals from a spark station. However, the irregular group frequency or spacing of the current trains due to the atmospheric discharges, differs from the nearly regular group frequency due to the spark transmitters, or the note produced by heat receivers from constant amplitude transmitter signals. The radio transmitters and receivers produce regular frequencies which can be more or less tuned to, while the atmospherics produce effects that tend to shock a resonant device, whatever be the period to which it is adjusted.

In times of more severe atmospherics the neutralizing and diminishing of effects described above may not be sufficient but may require still further neutralization to as sure practical radio receiving.

To neutralize the remaining effect of the atmospheric discharges, a second similar antenna 10 of Fig. 3 may be used, preferably in the same vertical plane as the first antenna, 1, and as indicated diagrammatically in Fig. 3. The second antenna 1() is adjusted for one half the frequency or twice the wave length of antenna, 1. This second antenna operates like the first, leaving a residue in the form of current excited in it by the atmospherics at the period to which it is adjusted. However, this second antenna` being of half the frequency of the first, is too far out of tune to be materially affected by signals to which the first antenna is adjusted. By coupling the rectifying circuit, 40, 45, 44 and 43, and circuit 40, 45, 4G, 41 and 42 and by coupling inductances 42 and 43 with inductance 47, as diagrammatically shown in Fig. 3, wherein rectifiers 41 and 44 cause the successive half waves to flow through inductance 42 and 43 in the same direction relative to 47, the frequency set up in 47 is made to be twice the frequency of the current in antenna 10. The circuit which includes inductances 47, 4S and condenser 49, is adjusted for the same frequency as that produced in inductance 47 and is Coupled through the circuit which contains inductances 16 and 17 with antenna 1, so that the current induced in 48 from inductance 17 is of a like frequency and in opposite phase to that induced in 47 from 42 and 43. This neutralizes the currents sets up by atmospherics; however, as practically no current is set up in antenna 10 by the signal impulses to the frequency of which antenna 1 is tuned, there is practically no neutralizing signal produced current set up in the circuit containing` 47, 48 and 49, and the signal therefore affects detector 20 to render the signal audible in telephone receiver 23 through the usual functioning of detectors 20 and condenser 21.

A diagram to illustrate neutralization in the audio-frequency circuit is shown in Fig. 4. In this two antennae 1 and 10 as heretofore described are shown. Antenna. 1 is coupled through inductances 15, 16 with circuit 5 which contains condenser 25, both these circuits being adjusted to the frequency of the radio signal, while antenna 10 and circuit 50 are adjusted to another frequency such that practically no current will be set up inthem by a .radio signal which acts upon antenna 1.

The circuits 240 and 241 which contain detectors 200 and 201 in the two portions of the receiving system, are adjusted so that the audio frequency currents due to atmospherics and similar objectionable discharges, set up in the circuits containing condenser 27 and inductance 300 and that containing 28 and 29, are practically alike. 29 and 300 i are opposing primaries coupled to the secondary 310 on the iron core 320.

The audio frequency currents due to the atmospherios, produce neutralizing magnetic fields in -secondary 310, while the radio signal currents due to the received radio signal, are practically only set up in antenna 1, so that the audio frequency currents due to the radio signal are set up Lin circuit 27, 300, and transferred to the telephqnereceiver 23 without material neutralization.

This neutralizing in circuits subsequent to the antenna circuit can be used in conjunction with other forms of antenna butother things being equal, as much neutralization as is practicable in the antenna circuit is desirable because, if strongcurrents exist in the antenna, sufficient current is frequently induced in the .subsequent circuits to render rectifiers and detectors temporarily inoperative, or cause them to function in some unsatisfactory manner.

lVhere it is impractical to maintain two antennae for use in neutralization, circuits as schematically shown in Fig. 5, may be used. In this, inductive windings, 6, 7 are connected to the radio receiver or amplifier 18, and adjusted to produce an approximately aperiodic circuit -or a circuit having relatively. the same :shocking or impulse excitation effect on the audio frequency circuits 62 and 72. Circuit 62 is adjusted to the audio frequency of the spark signal or the beat receiver note where constant amplitude radio signals are being received. Circuit 72 adjusted to one half the frequency of circuit 62.

By means of the transformers 74, 75, 76 and 52, 53, 54, and 55, the frequency of the current induced in coil 55 is brought to twice that in circuit 72 and coil 74, and to the same frequency as that induced in winding 5S through the transformers 64, 65, 66 and es, 69, 58.

Secondaries 55 and 58 are connected to bring the currents so induced into opposite phase in the circuit which contains the member 23, which is an amplifier, telephone receiver, or like instrument.

The shocking and irregular currents produced by atmospherics and by the improper operation of an amplifier, when used, produce practically an equal amount of effect in circuits 72 and 62, which effect is neutralized as above described. While at the same time audio frequency currents due to the signal, produce the chief effect in circuit. 62, which circuit is tuned to that tfrafsaiaa frequency. Any effect of the signal which may be produced in circuit 72 is rectified and its frequency changed to twice that of the signal, which only neutralizes the signal current to a relatively small extent.

Fig. 6 diagrammatically shows another arrangement of circuits for neutralization of the noise producing current due to atmospherics and amplifiers.

3 represents a receiver or amplifier. Circuits 30, 31, 32 and 33, 34:, are adjusted so that with the receiver or amplifier 3 connected, they provide circuits having two principal degrees of freedom such that the maximum amount of ycurrent of one half the audio frequency of the desired signal will flow through primaries 31 and 32, which latter inductances are adjusted in circuit for maximum current at one half the signal frequency, and so that the impulsive irregular current due to atmospherics or undesirable functioning of the amplifier, will give practically equal energy effect in inductances 31 and 32 and produce current of the signal frequency in inductances 33 and one half the signal frequency in inductances 31 and 32, or greater energy in 31 and 32 for elimination by dissipation or neutralization.

Vindings 31 and 36 being on the same transformer core 35, and windings 32 and 37 on a similar core 38, and the cores being magnetized to the knee of the saturation curve by battery 8 through windings 8O and 81, the current induced in the suitable connected windings 36 and 37 is made to be twice lthe frequency of the current in the windings 31 and 32 and the same as the frequency induced from windings 33 to 83. Windings 36, 37 and 83 are connected in the same circuit so that the currents produced therein are in opposition, whereby the currents due to atmospherics and other shocking disturbances are neutralized, while the audio frequency currents produced by the signal are not materially neutralized.

In Fig. 7, L1 and L2 are inductances in the same magnetic or electro-magnetic fields, which magnetic or electro-magnetic fields may be produced by periodic currents and impulse currents such as atmospheric discharges (static), or surges on a power line or opening and closing of a wire line telegraph circuit or the irregular operation of such devices as radio detectors and amplifiers. Inductances L:L and L2 may be the distributed inductances of two radio antenn, or they may be two secondaries coupled to a common primary; their functions are to pick up energy in the same ma netic or electro-magnetic fields.

ircuit L1, C1, and L3, circuit L5, C3, and L7 and circuit L10, C6 and L12 have a natural period of 2a. Circuit L2, C2 and L1 has a natural period of a Circuit L, C4 and LB with rectifier R2 and R2 change the alternating current of frequency n as received in L6 from L2, into pulsating current corresponding to an alternating current frequency of 271, which being impressed by coupling Ls and L10, on circuit C6, L10, L12 sets up an alternating current of frequency 2n in the latter circuit.

A field surge, shock or impulse impressed in Ll and L2, produces a current of frequency 2f/L in L1, C1, L3, which alternating current frequency is impressed on L1 via circuit L5 C3 L7. Also the same shock produces a current of frequency n in L2 C2 L1 which frequency is changed to alternating currency of frequency 2n and impressed on L11. L9 and L11 are connected so that the shock produced alternating currents reaching them will be opposed.

A field of frequency 2n acting on inductances L1 and L2 Will set up considerable current of that frequency in L1 G1 and L3 as compared with what Will be set up in L2 C2 L1 which latter is out of resonance for that frequency. Considerable current due to the field frequency 2n Will, therefore, pass through to L2, While Very little will pass through to L14. P1 and P2 are posts to which may be connected any device in which it is desired to use the alternating current derived from the periodic field and to eX- clude disturbance from shocking fields.

It is obvious that this principle of neutralization may be likewise carried out by forms of circuits, relative frequencies, methods of rectification, et cetera, other than these specifically described above and I do not limit myself to these particular illustrations and explanations of the principle.

Vhat I claim as my invention is:

l. In a radio signaling device, the combination With a plurality of receiving circuits susceptible to impulse excitation and having audio frequencies, of a neutralizing circuit and a circuit which contains rectifiers acting as frequency changing devices.

2. In a radio signaling device, the combination. With a pluralitv of A.

ROBERT H. MARRIOTT. 

